This invention relates to a method of polygon rendering for use in three-dimensional (3D) computer graphics(CG).
A conventional method of polygon rendering of the type described includes coordinate rasterization, pixel shading, hidden surface removal, and the like. For example, an application of such polygon rendering is in the classical three-dimensional (3D) graphics pipeline which comprise the following three steps: vertex shading, coordinate transformation and polygon rendering. Herein, the invention is applied for implementation of the final step, polygon rendering. Another example is font rendering where the structure of a character is rendered to either a display or a printing device.
Conventionally, polygon rendering is performed with a fixed bit resolution, determined by worst case consideration in order to avoid numerical overflow. An example of such method is disclosed in "A Fast Shaded-Polygon Renderer", by R. W. Swanson and L. J. Thayer, Computer Graphics 20, 4, 1986, (Proceedings of SIGGRAPH 1986), pp. 95-101.
In the interim, the majority of the coordinate and color spans are small in which low bit resolution offers sufficient accuracy in many computer graphics scenes. However, in the conventional method of polygon rendering, no consideration is made about reduction of the required number of processing cycles by first measuring the coordinate and color spans and then selecting an appropriate word size. In other words, no consideration is made as regards acceleration of interpolation process resulting from the reduction of the required number of processing cycles.